The determination of chlorophylls a and b together with 14CO2 fixation in the same plant tissue samples

A simple, efficient, and inexpensive method for measuring radioactivity as well as chlorophylls a and b in a large number of plant tissue samples is presented. Chlorophyll is determined following extraction with dimethyl sulfoxide or N-N'-dimethylformamide. The solvent is then evaporated on glass-fiber filters and bleached under light. The filter disks are counted together with the cleared plant material.     

A new survey of Brazilian marine algae for agglutinins

Aqueous protein extracts from 30 Brazilian marine algae were examined for haemagglutinating activity using native and enzyme-treated rabbit, chicken, sheep and human erythrocytes. Most extracts agglutinated at least one of the blood cells used. Sheep and rabbit erythrocytes were more suitable for detection of the agglutinating activity. The minimum protein concentration necessary to produce positive agglutination was usually lower with enzyme-treated erythrocytes than native ones. The five algal protein extracts showing the greatest haemagglutination titre were tested for sugar-binding specificity. Only the activity present in the green alga Cauler pacupressoides was inhibited by simple sugars and not by the glycoproteins tested. The activity of the other four extracts was inhibited by at least one of the glycoproteins utilised. This revised version was published online in August 2006 with corrections to the Cover Date.     

Some common properties of lectins from marine algae

Twelve kinds of lectins isolated from four species of marine algae, Boodlea coacta (Chlorophyta) and Hypnea japonica, Carpopeltis flabellata and Solieria robusta (Rhodophyta), were compared for their chemical and biological properties. These lectins were proteins or glycoproteins, similar to terrestrial plant lectins. However, unlike most terrestrial plant lectins, they had a small molecular size (4,200 to 25,000 daltons), were mostly monomeric, and had no affinity for monosaccharides. They strongly agglutinated trypsin-treated rabbit erythrocytes, and their activities commonly were inhibited by glycoproteins bearing N-glycans. From hemagglutination-inhibition tests with various glycoproteins and related compounds, it was found that B. coacta lectins recognize high-mannose N-glycans; H. japonica lectins complex N-glycans, and C. flabellata and S. robusta lectins recognize both types of N-glycans.     

Hemolymph functions in Mytilus californianus: The cytochemistry of hemocytes and their responses to foreign implants and hemolymph factors in phagocytosis

The hemocytes of Mytilus californianus are of three types: small and large basophils and large granular acidophils. The basophils contain lysosomal enzymes and phagocytose colloidal carbon. Agglutinins for yeast and human A Rh+ve erythrocytes are present in plasma, but are not needed for effective phagocytosis; in vitro both acidophilic and basophilic hemocytes rapidly phagocytose these particles. Plasma proteins, analyzed electrophoretically, are under strong homeostatic control. When Mya arenaria mantle is placed orthotopically on M. californianus mantle, the implant is invaded by host hemocytes in a manner consistent with that described in other published reports on molluscan graft rejection. Steady state is achieved by 26 days postimplant. Second- and third-set implants are rejected more rapidly than are first-set implants, but this is not a specific response. Third-set implants elicit a host cellular response that is more localized than the response to first-set implants. These data do not permit conclusions with respect to memory in these molluscan immune responses, but do imply a qualitative “improvement” in this quasi-immune response of M. californianus.     

Epidemiology of typhoid carriers among blood donors and patients with biliary, gastrointestinal and other related diseases

Enteric fever due to Salmonella Typhi is a major public health problem. Typhoid carriers have high titres of Vi agglutinins in their sera. We worked out the baseline data for Vi agglutinins from 705 healthy blood donors (controls) by ELISA and compared it with 446 patients with biliary, gastrointestinal and other related diseases (cases). The samples were divided into five groups based on the disease condition of the patients from whom they were collected. Group A (n=196) consisted of patients with stones in the gall bladder/common bile duct and Group B (n=27) with gall bladder carcinoma. Group C (n=33) comprised patients with carcinoma of the pancreas/ampulla, obstructive jaundice and/or cholangiocarcinoma. Group D (n=112) had patients with acute/chronic pancreatitis, abdominal pain, intestinal obstruction, peritonitis, carcinoma oesophagus, chronic diarrhoea, gastrointestinal bleeding and dyspepsia. Group E (n=78) included patients with miscellaneous diseases. The mean absorbance value obtained for healthy subjects +3 standard deviations was taken as the cut-off value for a positive typhoid carrier. In Group A, 10.2% samples were positive; in Group B, 7.4%; in Group C, 12.0%; in Group D, 9.8% and in Group E, 9.0%. There was a highly significant (P <0.001) increase in the presence of Vi agglutinins in the cases compared to the controls. High prevalence of typhoid carriers occurs in patients with biliary, gastrointestinal and other related diseases. Vi serology employing highly purified Vi antigen offers a practical and cost-effective way of screening for S. Typhi carriers.     

Turnover and transport of agglutinins in conjugatingChlamydomonas gametes

Summary During gamete-gamete adhesion in the unicellular green algaChlamydomonas eugametos, the sexual adhesion molecules or agglutinins that are located on the flagella are subject to tip-oriented migration and rapid inactivation. It is demonstrated that sexual adhesiveness is maintained by incorporation of additional agglutinins, recruited from a cellular pool. The location of this reservoir is unknown but, as indicated by its insensitivity to the chaotropic agent guanidine thiocyanate, it appears to be distinct from the large amount of agglutinins on the plasma membrane of the cell body. By viewing flagella of conjugating gametes in a confocal scanning laser microscope after immuno-labelling of the agglutinins, evidence was obtained for a linear arrangement of the agglutinins in two rows on the flagellar surface. This suggests that after insertion at the base of the flagellum, the agglutinins follow linear tracks to the tip and that the transport system is confined to two longitudinal domains. It is estimated that the half-life of flagellar agglutinins drops from 1–2 h in nonconjugating gametes to 1 min during conjugation, which suggests that after incorporation at the flagellar base, the agglutinins migrate to the tip with a velocity of 100 nm/s. Presumably after arrival at the tip, the molecules are inactivated. It is postulated that rapid turnover and transport of agglutinins are required for optimal signalling between partner gametes.Abbreviations BSA bovine serum albumine - CHI cycloheximide - CSLM confocal scanning laser microscope - GA glutaraldehyde - GTC guanidine thiocyanate - GAM-IgG goat-anti-mouse immuno-globuline - mAb monoclonal antibody - mt mating type - PBS phosphate-buffered saline - SDS sodiumdodecyl sulphate - TRIS tris-(hydroxymethyl)-aminomethane     

Immune response of the prawn, Macrobrachium rosenbergii, to bacterial infection

Serum agglutinins of Macrobrachium rosenbergii found in normal serum were reactive toward eight bacterial species and type A human red blood cells. Absorption studies indicated the ability of the agglutinins to distinguish between different bacterial species as well as between certain bacteria and red blood cells. Agglutinin titers were approximately the same for the bacteria, whereas those for red blood cells were significantly higher. A virulent strain of Vibrio anguillarum was used in infectivity experiments. An LD₅₀ value was determined between 5 × 10⁶ and 10⁷ cells/animal, and an attempt was made to immunize the animals using formalin-killed cells. The animals did not respond to the vaccination, as there was neither an increase in the level of circulating agglutinins nor the LD₅₀ level 6 days after injection. Structural and functional traits of serum agglutinins are markedly different from vertebrate antibodies.     

Stress-dependent trade-off Between Immunological Condition and Reproductive Performance in the Polygynous Red Bishop (<Emphasis Type="Italic">Euplectes orix</Emphasis>)

According to life-history theory, a condition-dependent trade-off between reproductive performance and immune function might be expected, with only superior individuals being able to allocate many resources into reproduction without having detrimental effects on their immune system. However, little attention has been paid to the possibility that annual variations in environmentally and socially induced stress levels modify this trade-off. We analysed haematological parameters and investigated the relationship between male immunological condition and reproductive performance as measured by reproductive effort and success in a colony of the highly polygynous red bishop (Euplectes orix) for five consecutive breeding seasons. Haematological parameters can be used to assess an individuals’ stress level, and especially the heterophile/lymphocyte ratio (H/L ratio) is known to increase in response to a wide variety of stressors. Relative basophile counts, heterophile counts, lymphocyte counts, absolute leukocyte counts and H/L ratios of territorial males varied significantly among seasons. Both relative heterophile counts and H/L ratios were significantly positive related to overall breeding activity within the colony as measured in terms of total number of nests accepted and total number of eggs laid in the study colony within a breeding season. The relationship between immunological condition (as assessed by relative lymphocyte and heterophil counts and the H/L ratio) and both male reproductive effort (as measured by the number of nests built by the territorial males) and reproductive success (as measured by the number of nests accepted) varied considerably among seasons, ranging from significant negative to significant positive correlations. Across seasons, we found a significant negative relationship between the within-season correlation coefficients of individual H/L ratios against reproductive performance and the average H/L ratio of all territorial males in that season. Thus, a positive association between the immunological condition of a male and his reproductive performance (indicated by a negative correlation between H/L ratio and reproductive performance) exists only in seasons with high average H/L ratios (i.e. high average stress levels). We conclude that the trade-off between immunological condition and male reproductive performance might be important only in seasons with an overall reduced level of male immunological condition due to environmentally and/or socially induced stress and immunosuppressive conditions.Co-ordinating editor: L.D. Hurst     

Mushroom lectins: Current status and future perspectives

Lectins are nonimmune proteins or glycoproteins that bind specifically to cell surface carbohydrates, culminating in cell agglutination. These are known to play key roles in host defense system and also in metastasis. Many new sources have been explored for the occurrence of lectins during the last few years. Numerous novel lectins with unique specificities and exploitable properties have been discovered. Mushrooms have attracted a number of researchers in food and pharmaceuticals. Many species have long been used in traditional Chinese medicines or functional foods in Japan and other Asian countries. A number of bioactive constituents have been isolated from mushrooms including polysaccharides, polysaccharopeptides, polysaccharide–protein complexes, proteases, ribonucleases, ribosome inactivating proteins, antifungal proteins, immunomodulatory proteins, enzymes, lectins, etc. Mushroom lectins are endowed with mitogenic, antiproliferative, antitumor, antiviral, and immunestimulating potential. In this review, an attempt has been made to collate the information on mushroom lectins, their blood group and sugar specificities, with an emphasis on their biomedical potential and future perspectives.